<template>
    <div class="helper">
        <span class="left">{{unFinishedTodoLength}} items left</span>
        <span class="tabs">
            <span v-for="state in states"
            :key = "state"
            :class = "[state, filter === state?'actived':'']"
            @click = "toggleFilter(state)"
            >
            {{state}}
            </span>
        </span>
        <span class="clear" @click="clearAllCompleted">Clear Completed</span>
    </div>
</template>
<script>
export default {
    props:{
        filter:{
            type:String,
            required:true
        },
        todos:{
            type:Array,
            required:true
        }
    },
    computed:{
        unFinishedTodoLength(){
            return this.todos.filter(todo => !todo.completed).length
        }
    },
    
    data(){
        return{
            states:['all','active','completed']
        }
    },
    methods:{
        clearAllCompleted(){
            this.$emit('clearAllCompleted')
        },
        toggleFilter(state){
            this.$emit('toggle',state)
        }

    },
}
</script>
<style lang="stylus" scoped>
.helper{
    font-weight 100px
    display flex
    justify-content space-around
    padding 5px 0
    line-height 30px
    background-color #ffffff
    font-size 14px
    -webkit-font-smoothing:antialiased
   
    }
.left,.clear,.tabs{
    padding 0 10px
    box-sizing border-box

    }
.left,.clear{
    width 150px
    }
.left{
    text-align left 
    }
.clear{
    text-align right 
    cursor pointer
}
.tabs{
    width 200px
    display flex
    justify-content space-around
    *{
        display inline-block
        padding 0 10px
        cursor pointer
        border 1px solid rgba(175,47,47,0)
        &.actived{
            border-color rgba(175,47,47,0.4)
            border-radius 5px
            }
    }  
    }
</style>
